Suffolk Reporter

Research by the Atacama Cosmology Telescope (ACT) collaboration has resulted in new images of the universe's earliest light, providing unprecedented clarity of the cosmic microwave background (CMB) radiation. This radiation was visible only 380,000 years after the Big Bang. The international team includes astrophysicist Neelima Sehgal from Stony Brook University, whose group played a key role in analyzing this afterglow light.

The images reveal light that traveled over 13 billion years to reach the ACT in Chile and show the universe at about 380,000 years old. Suzanne Staggs, Director of ACT and Henry deWolf Smyth Professor of Physics at Princeton University, explains: “We are seeing the first steps towards making the earliest stars and galaxies.” She notes that these images show not just light and dark but also high-resolution polarization of light.

These findings confirm a simple model of the universe and eliminate most competing theories. The results will be presented at the American Physical Society Annual Meeting on March 19. Jo Dunkley, Joseph Henry Professor of Physics and Astrophysical Sciences at Princeton University, highlights that by examining this early time, scientists can piece together how our universe evolved.

ACT's measurements have refined estimates for the age of the universe and its growth rate today. They confirmed a lower value for the Hubble constant with increased precision. Sehgal emphasizes that their work tests the standard cosmological model without finding any inconsistencies.

The Stony Brook team has been involved in CMB analysis for over a decade. With ACT observations completed in 2022, focus is shifting to the Simons Observatory in Chile, where Stony Brook is an institutional partner.

Sehgal’s research is funded by various organizations including NSF and DOE. The project receives support from institutions like Princeton University and University of Pennsylvania among others.

The new ACT data are available publicly on NASA’s LAMBDA archive. Pre-peer review articles related to this release can be found on the ACT website and arXiv.org.